摘要
The microstructure and tensile properties of the as-cast and solution treatment Mg-4.5Zn-1Y-xNd-0.5Zr （x=0, 1 wt.%, 2 wt.%, 3 wt.%） alloys were investigated. The results showed that the microstructure of Mg-4.5Zn-1Y-0.5Zr alloy consisted of α-Mg, Zn-Zr, W （Mg3Y2Zn3） and I （Mg3YZn6） phases. With the addition of Nd, I-phase disappeared and Mg3Y2Zn3 phase changed into Mg3（Nd,Y）2Zn3 phase. When the content of Nd reached 3 wt.%, T phase, i.e., ternary Mg-Zn-Nd phase, formed. In addition, with the increase of Nd content in the alloys, the secondary dendritic arm spacing decreased, while the amount of intermetallic phases increased. For as-cast Mg-4.5Zn-1Y-xNd-0.5Zr alloys, after solution treatment, microsegregation was eliminated and the shape of eutectic structure of α-Mg＋W transformed from lamellar into spherical. The tensile strength and elongation of Mg-4.5Zn-1Y- 3Nd-0.5Zr alloy were increased from 219.2 MPa and 11.0% to 247.5 MPa and 20.0%, respectively.
The microstructure and tensile properties of the as-cast and solution treatment Mg-4.5Zn-1Y-xNd-0.5Zr （x=0, 1 wt.%, 2 wt.%, 3 wt.%） alloys were investigated. The results showed that the microstructure of Mg-4.5Zn-1Y-0.5Zr alloy consisted of α-Mg, Zn-Zr, W （Mg3Y2Zn3） and I （Mg3YZn6） phases. With the addition of Nd, I-phase disappeared and Mg3Y2Zn3 phase changed into Mg3（Nd,Y）2Zn3 phase. When the content of Nd reached 3 wt.%, T phase, i.e., ternary Mg-Zn-Nd phase, formed. In addition, with the increase of Nd content in the alloys, the secondary dendritic arm spacing decreased, while the amount of intermetallic phases increased. For as-cast Mg-4.5Zn-1Y-xNd-0.5Zr alloys, after solution treatment, microsegregation was eliminated and the shape of eutectic structure of α-Mg＋W transformed from lamellar into spherical. The tensile strength and elongation of Mg-4.5Zn-1Y- 3Nd-0.5Zr alloy were increased from 219.2 MPa and 11.0% to 247.5 MPa and 20.0%, respectively.
基金
supported by National Key Technology R&D Program(2011BAE22B01-1)
the National Basic Research Program of China(2013CB632205)
